Effects Of Tannin In Sainfoin On Protein Protection Of Diets

The two experiments were carried out to study the effects of the different dosage of tannins on the protein degradability in Situ and on the protein protection in ruminant diets. Experiment 1: Three healthy crossbred Mongolian wethers fitted with permanent rumen fistula were chosen to measure the degradability in Situ of DM and CP of the high-quality soybean meal treated with 6 levels(0%,5%,10%,15%,25%,35%)of tannin acid. The results showed : (1) Hydrolyzed tannin declined the degradability of DM and CP of soybean meal; the effect of 5% tannin acid was obvious, and the degradability of DM and CP of soybean meal with 10%～15% tannin acid declined to a great extent. (2) The appropriate dosage of tannin depended on the degradability of soybean meal; the overripe heated soybean meal did not need to protect. Experiment 2: To choose the appropriate dosage of tannins for the diets in sheep, three High Mountain Fine-wool wethers fitted with permanent rumen fistula were used and the 3 ×3 Latin square design were adopted to study the effects of tannins in Sainfoin on protein protection of the diets, measured items included the rumen metabolic parameters, the appatent digestion of all nutrients and the appatent retention of N in sheep. The results indicated: (1) Difference of the appatent digestion and absorption of DM, OM and P were no significant (P>0.05) among three treatments, but the trends of treatments B and C lower as contrast to treatment A on the apparent digestibilities of NDF, ADF and Ca (P=0.369, 0.335, 0.087)were observed. (2) The appatent retention of N of diet with 3.40g/kgDM tannis in Sainfoin was higher significantly (P<0.01) than the others with 1.70g/kgDM and without tannis in Sainfoin. Also the negative effects on the appatent digestion of N and synthesis of rumen bacterial protein not occurred at 3.40g/kgDM(including 3.03g/kgDM condensed tannin) of tannis in Sainfoin. Therefore under the condition of this experiment, the preferable effect on the protein protection was found at 3.40 g/kg DM the tannis in Sainfoin. (3) Besides the trend towards the lower pH value in the rumen liquid (P=0.259), other metabolism parameters of rumen were not significantly affected negatively by tannis in Sainfoin and the stability of the dynamic changes of total nitrogen, the ammonia nitrogen, the urea nitrogen and the protein nitrogen level in the rumen liquid was maintained favorably. (4) Considering the diet combinations, three treatments were all reasonable, and the effect of the diet with the Sainfoin added together with the corn-stalk and wheat-straw was best. It was clearly seen that Lucerne be replaced partly or totally by Sainfoin was feasible.